As examples of conventional microneedle arrays, those as described in Patent Document 1 and Patent Document 2 are known.
A percutaneous absorption formulation holding sheet (microneedle array) described in Patent Document 1 has a structure as illustrated in FIG. 33. There is a support body 1001, and percutaneous absorption formulations (microneedles) 1003, each of which is substantially in a conical fine needle shape, are firmly fixed on the support body 1001. The percutaneous absorption formulations 1003 are punctured into the skin.
Moreover, Patent Document 1 also discloses a percutaneous absorption formulation holding tool. The percutaneous absorption formulation holding tool is composed of a main body having penetration holes, and percutaneous absorption formulations, each of which is in a needle shape and held inside the respective penetration hole.
Moreover, a percutaneous administration formulation (a microneedle array) described in Patent Document 2 has a structure as illustrated in FIG. 34. There is a support body 1005, and a plurality of fine needles (microneedles) 1007 is firmly fixed on the support body 1005. The fine needle 1007 is substantially in a conical shape, composed of a first portion 1009 on the top end side (the upper side of FIG. 34) and a second portion 1011 on the base end side (the lower side of FIG. 34). The first portion 1009 was prepared, for example, by mixing a base, which is comprising a high-molecular substance having an in vivo solubility and a thread-forming property, with an objective substance such as a local anesthetic medicine and water, and thereafter, by drying and solidifying thereof. Moreover, the second portion 1011 was prepared, for example, by mixing a base, comprising a high-molecular substance having an in vivo solubility and a thread-forming property, with water, and thereafter, by drying and solidifying thereof.
On the other hand, by using a metallic base part, there is also a development of a microneedle medical formulation, having a biodegradable substance containing an objective substance at the tip part thereof (Non-Patent Document 1).
Further, there are various developments of safe medical formulations by which a desired volume of the objective substance can be administrated more surely.